You should be doing the drum clean at 90 degrees not doing it at 30degrees. 30 degrees is cold water, you need hot water to kill the germs and bacteria in your washing machine, you should not be washing clothes is cold water either, coloured clothes should be washed at 40degrees, whites should be washed at 60 degrees, and things like towels and kitchen cloths should all be done on 90 degrees, If you follow what I have said you will not get Mould in your washing machine, it will also hello to keep dust and fluff level down to a minimum